1. Field of the Invention
This invention relates to histone deacetylase inhibiting agents. In particular, the present invention relates to novel hydroxamic acid derivatives or pharmaceutically acceptable salts thereof for anticancer agents or other therapeutic agents based on their histone deacetylase inhibitory activity.
2. Description of the Art
Cancer is one of the most common cause of death in the developed world. Despite advances in the diagnosis and management of many cancers, only minor improvements in cure and survival rates have been realized. The incidence of cancer is rising as a result of ageing populations and complex environmental and lifestyle factors. Cancer imposes great costs on society and individuals via premature disability, mortality and high treatment costs. To date many anticancer drugs have been investigated, but no satisfactory drugs have been discovered. So an anticancer drug with reduced toxicity and high therapeutic effect has been desired.
Key nuclear processes such as DNA replication, transcription, repair, and rearrangements during differentiation are influenced by chromatin structure and the binding of regulatory proteins to DNA. These processes can be modulated by the acetylation level of nucleosomal histones. Histone deacetylases and the family of histone acetyltransferases are involved in determining this acetylation of histones, which play a role in regulation of gene expression. Increasing evidence indicates that cellular proteins involved in the regulation of proliferation and differentiation exert their function by recruitment of histone acetyltransferases or deacetylases. In various cases aberrant histone acetylation has been linked to malignant disease.
A number of histone deacetylase inhibitors have been identified that induce cultured tumor cells to undergo growth arrest, differentiation, and/or apoptotic cell death. Several of these agents, the hydroxamic acid based histone deacetylase inhibitors in particular, inhibit tumor growth in animals at doses that cause little or no toxicity [Paul A. Marks et al., Current Opinion in Oncology, 2001, 13, 477-483].